In large mixing, bowl, beat together butter and sugar. Add corn syrup, egg, and vanilla; blend well. Add peanut butter and blend.
In a separate bowl, stir together flour, baking soda, and salt. Gradually add dry ingredients to peanut butter mixture, blending well. Refrigerate one hour or until dough is firm enough to handle.
Preheat oven to 350 degrees.
Roll dough into 1-inch balls; roll in sugar. Bake on ungreased cookie sheet for 10 minutes or until lightly brown around edges. Cool slightly before removing to wire rack.
Yield: About 5 dozen cookies.